Multiple-bit underreamer



A. L. SEGELHURST.

MULTiPLE BIT UNDERHEAMEH.

APPLxcATxoN HLED MAR. 28, 192:.

`-reainer body.

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AUGUST L. SEGELHR-ST, OF W'HITTIER, CLIEORNIA.

MULTIPLE-BIT Specification of Letters Patent.

onlinr-innemen.

.tipplication lerl March 28, 1921. Serial No. 456,364.

To rf/Z 'zu/mm it may concern:

lle it known that l, roi's'r'ii. Suoni,- nons'r, a citizen oi' the United States, residing at llvhittier, county of Los Angeles, State of California, have invented a new and useful `lvlultiple-Bit Underreanim, of which the following is a specification.

My invention relates to underreaniers, being, more, particularly an underreanier havino* two or inore cutting lugs or jaws.

`rl`he principal object of niy invention is to produce an underreamer of the class described of strong and durable construction which may be readily assembled and which is eliicient in operation.

Other object: and advantages will appear' hereinafter from the following specification and drawings.

Referring to the drawings which are for illustrative purposes only,

Figure l is a vertical sectional view of one forni of my invention. the aws being shown in collapsed position.

Fig. :2 is a ligure similar to Fie. l, showing' the jaws in expanded position.

Fig. 3 is a sectional plan view on line 3 3, Fig. 2. i

Fig. et is a sectional plan view on line Lite, Fig. l.

Fig. 5 is an inverted plan view of the Fig. 6 is a perspective view of the center block, and

l? l is a. perspective view of the spider.1

AThe undcrreainer consists of a body ll. havingT a central bore lil which terminates at its lower end in a shoulder 13 formed at the lLipper end ot' a tapered recess le, such tapered recess also being provided with an intermediate shoulder l5. as is clearly shown in Figs. l and 2.

18 designates a center block provided with a flange l) which engr the shoulder l5 in the recess 14. such center block being tapered above the flange and fitting' the walls oi the recess above such flange. The lower end of the center hloch is substantially square in cr section and is provided with upper and lower beveled fares 20 and 2l for the purposes hcreiimtter` described. y

The center hioclr is hollow to receive a mandrel 22 and is also provided with radially' extending slots 24s through which. extend arins 25 which support the jaws indicated at 2G, such jaws being provided with shanls .2T which are provided5 in turn, with openings 28 to receive the arins 25.

lt is understood that the mandrel is in` serted in the center block lrorn the. top of the saine, the arnis 25 being received by the slots Q4. For the purpose ot' filling` such slotsafter the mandrel is in place, provide a spider 3() j n'ovided with a. head 3l and downwardly extending legs 32, there, being a. leg 32 for each slot '24. rThe head of the spider rests upon the upper end oi' the center block and the legs 352. extend downwardly lilling the slots 2s in the center block. The head 3l of the spider engages against the shoulder 13 in the underreainer body and receives the lower end of a coiled spring 33 on the mandrel 252', the upper end of such spring engaging suitable nuts on the upper end oiv the mandrel.

lt will be understood that the mandrel is slidable vertically through the head 3l of the spider and in the center block.

The center block below the flange l?) is shaped to receive the Shanks Q7 of the jaws 2G, such shanlrs being provided with beveled faces 38 which engage the beveled faces 20 and 2l of the center block when thejaws are' in expanded and collapsed positions respectively.

The recess in the lower end oi the mandrel is formed with vertical exteniiling ways 4f() which receive the shanlis oi' the cutting jaws, as shown in Fig. 3, the center block being substantially circular in torni with flat faces l2 formed thereon and the recess in the body of the underrean'ier being' similarly iorrned to receive the center block. shaping); ot the center block is ior the purpose of having a center bloeit voli niaXiniuin size withoutcntting down the size of the shanlrs oi? the ja thereby giving the jaws maximum strength.

rilhe center block and spider are held in the body of the underreainer by means of Uf shaped bolts flo, clearly shown in Fig. il, such bolts extending through the body and err gagging the center block and legs of the spider, as shown in Figs. l, 2 and s, suitable nuts being provided for the bolts, as indicated at 46.

ln the form shown, *he cutting jaws are rllhis used.

.Vlhe operation of the parts is clearly shown in Figs. l and 2j nFig. l the mandrel is shown pulled downwardly from the body which allows i the jaws to collapse into the position shown in Fig. l, the jaws being cut away on their inner face as shown at 50 so that the same will clear the lower end of the center block and allow the jaws to collapse into theposition shown.

, In Fig. 2 the mandrel has moved into its upper positionv due to the action of the spring 38, the jaws being moved upwardly until the upper ends 0f the shanks and jaws engage the flange 19 on the center block, the beveled faces v38 on the jaws coming, into contact with the beveled faces 20 on the center block and the upper ends of the shanks above such beveled faces 4fitting against the sides of the center block, as shown in Fig. 2, such construction providing` a firm connection between the body of the underrealner and the jaws.

Shoulders 52 are also provided on the jaws which engage the lower edge of the under- .Y reamer-body as shown'f'in Fig. 2.

il claim as `my invcntion:

l. 1n an underreamer; a body having va tapered recess extending into the lower end thereof; a circular shoulder in said recess; a center block Yextending into said'recess having a central bore and slots extending radially therefrom; a flange) on said center block engaging said shoulder; bolts in said vbody engaging said center block; a` mandrel slidably mounted in said body; radially extending arms on the lower end of said mandrel; a plurality of cutting lugs; shanks on said lugs extendinginto said recess and each having` an arm receiving opening therein; a spider on the upper end of said center block; legs on said sp`der extending into the slots in said center block; a coiled spring on said mandrel above said spider; and means on said mandrel for' confining said spring.

2. In an ui'iderreamer; a body having' a tapered recess extending into the lower end thereof; a center block extending into said recess having a central bore and slots eX- tending radially therefrom; means for securing'said center block in said body; a mandrel slidably mounted in said body;

inanimarms on the lower end of said mandrel eatending outwardlythrough the radial slots in the center block; a spider on the upper end of said center block; legs on said spider extending into` the slots in the centenblock i above the arms on said mandrel; a plurality.

of cutting lugs, Shanks onl said lugs entending into said recess in the lower end of'the body; and elastid means for pulling said mandrelv upwardly.

3. ln an underreamer; a body having a vrecess extending into its lower end; a center bloclr in said `recess; means for securing.

said center 'block in said body; said center block having a central bore and slots extendingoutwardly through the slots in said een. ter block; a spider; a head on Said spider seated on the upper end of .'said center block; legs on said spider extending vdownwardly into the slots in said centerblock 'a plurality of cutting lugs having openings flange on said center block engaging the intermediate shoulder in said recess; 'means for securing said center block in said recess; a mandrel slidably mounted in said center block; arms on said mandrel extending through the slotsin the center block; a plu-` ralit of cutting lugs engaging said arms; '-a coiled springon said mandrel above the center block and nuts on said mandrel engaging the upper end of said spring.

5. In an underrea'mer; a body; .a center block in said body having radially extending slots extending downwardly from the upper end thereof and 'a central opening to receive a mandrel; a mandrel; radially einl asi ice

Atending` arms on the lower end of saidmandrel, said arms extending through the slots in said center block; means for filling said los slots above said arms; 'cutting lugs'mounted on said arms; and means for placing an elas tic tension on said mandrel.

In testimony whereof, Iliave hereunto set my hand at Los Angeles, California, this 22nd day of Marchyl92 l A AUGUST L; SEGELHORST. 

